--  @testpoint:opengauss关键字add(非保留)，作为函数名
--关键字不带引号-成功
drop function if exists add;
create function add(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/
--清理环境
drop function add;

--关键字带双引号-成功
drop function if exists "add";
create function "add"(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/
--清理环境
drop function "add";

--关键字带单引号-合理报错
drop function if exists 'add';
create function 'add'(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/

--关键字带反引号-合理报错
drop function if exists `add`;
create function `add`(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/